Google's video service will now offer independent audits of campaigns to show brands when ads were served, viewed and validate the internet traffic.

YouTube's new measurement regime was accredited by industry group Media Ratings Council, which works with digital and traditional media suppliers to impose uniform standards for advertising metrics.

The move got the attention of Mr. Pritchard, P&G's chief brand officer, who has been a leading voice in demanding more transparency in the digital media supply chain. Digital ad inventory has been infested by fraudulent impressions and faulty data for some time.

"Google's announcement to bring more media transparency is important progress that will help move the industry forward," Mr. Pritchard was quoted as saying in YouTube's announcement on Tuesday. "At P&G, we are encouraged by Google's actions, which should make a positive impact on creating a clean and productive media supply chain."

Mr. Pritchard has been outspoken in calling on publishers and ad platforms to clean up their digital inventory and prove their worth to brands.

Google had already been working with MRC and other industry watchdogs for years to implement standards of viewability and stamp out fraud on its own properties and on outside publisher sites.

The ecosystem is evolving, however, as video becomes a more prevalent ad format on mobile and desktop devices and across Google's DoubleClick ad platform, which delivers ads to publishers that use it for their own ad management.

"These MRC audits will span across all video available through these buying platforms, including YouTube and partner inventory," said Babak Pahlavan, Google's senior director of product management, analytics solutions and measurement, in the announcement.

Agencies and brands rely on those companies to help understand where ads run and how they perform, but they have to be sure the data they get from platforms like YouTube, Facebook and others are accurate.

Advertisers have been concerned about the accuracy of data coming back from their digital ad campaigns, showing how many impressions ads get and how long people view them.

Last year, Facebook had to adjust its measurements after flaws were uncovered in how it measures unpaid video posts. The metrics problems did not impact paid ads, according to Facebook, but it still showed how platforms can make mistakes with the numbers.

Facebook has since adopted similar MRC auditing options, and promised deeper insights into how ads perform on the social network. Facebook also has been expanding relationships with third-party ad tech partners like Integral Ad Science and Moat.

The Association for National Advertisers has been pushing platforms to open up about their data, and let the industry get a better look insider their "walled gardens."

"Our goal is to create transparency for the advertising supply chain," Bob Liodice, ANA's president and CEO, said in Google's announcement.